chapter  1
Introduction
Pages 2

Traditionally, most of the mechanical problems in elementary physics and mechanic courses were solved by ignoring the effect of friction because the inclusion of frictional forces made the analysis too complicated. Although friction has been ignored in many classic mechanical problems, it is a very important phenomenon in our daily life. Left to act alone, it is the frictional force that brings every rotating shaft to a halt. In today’s automobiles, for instance, about 20% of the engine power is consumed to overcome internal frictional forces [1,2]. It seems that friction causes expenditure on unnecessary energy to overcome it. On the other hand, without friction, no one can walk, hold a pen or pencil and, even if they could, it would not allow writing. Furthermore, it would not be possible to have a wheeled transportation system without friction.